Photoeffect cross sections of several rare-earth elements for 323-keV photons

Abstract

Total-attenuation cross sections of the oxides of rare-earth elements such as La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, and Er, and also ${\mathrm{NaNO}}_3$ and ${\mathrm{NaNO}}_2$ have been measured in a narrow-beam geometry setup at 323 keV. The total-attenuation cross section for oxygen was obtained as the difference in ${\mathrm{NaNO}}_3$ and ${\mathrm{NaNO}}_2$ cross sections. Using this, the total-attenuation cross sections of the individual lanthanides have been obtained with the aid of the mixture rule. From these, the photoeffect cross sections were derived by subtracting the scattering contribution. These values are found to agree well with Scofield’s theoretical data [University of California Report No. UCRL 51326, 1973 (unpublished)].